Information recording apparatus

ABSTRACT

An information recording apparatus such as an optical disc that can avoid an unrecordable condition between a power-on operation and an available state for recording thereby to solve a problem that an image taking chance is missed in a recording step, wherein its constitution is such that: receiving a command to turn on the apparatus after switching, a system controller drives a power-supply circuit to activate a drive controller and a memory controller; if the optical disc is not replaced while in power-off operation by a sub-battery, the system controller issues a request for high-speed activation, based on information stored in an EEPROM, to the drive controller, and drives plural drive control units one after another thereby to establish an activation period confirmedly, allowing the memory controller to accept a request for a recording start from the system controller without waiting for a report of activation completion to be issued by the drive controller.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This is a continuation of U.S. patent application Ser. No. 11/515,108,filed Aug. 31, 2006, which is a continuation of U.S. patent applicationSer. No. 10/424,456, filed Apr. 25, 2003, which claims priority to JPApplication No. 2002-123386, filed Apr. 25, 2002, the entire disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for recording informationonto a recording medium, particularly to operations from a power-onevent of the apparatus to a state in which the apparatus is capable ofstarting a step to record information onto the recording medium.

A conventional optical disc drive suffers from disadvantageous long timefor its activation, i.e., from a halt condition of disc rotation to asteady-state condition of the rotation. Thus, an information recordingapparatus such as the type for recording an image taking signal onto arecording medium, can not record the image taking signal onto therecording medium during some time lapsing after it has turned on,raising a problem that an image taking chance is missed.

In order to solve the problem, in an apparatus disclosed in JP-A No.93918/1998, the following method is adopted to avoid a state in which animage taking signal cannot be recorded onto a recording medium.

In the apparatus cited above, after the user turns on the power-supplyof the apparatus, a compressed and encoded signal obtained as a resultof compression and encoding steps carried out on an image taking signalis stored temporarily in a memory means till a disk drive unit employedin the apparatus enters a state of being capable of recordinginformation onto a recording medium. The compressed and encoded signalis referred to hereafter simply as an image taking signal. Then, at astage the disk drive unit employed in the apparatus enters a state ofbeing capable of recording information onto a recording medium, arecording means employed in the disc drive unit starts a recordingoperation while the operation of storing the following image takingsignal into the memory means is being continued.

If the amount of information transferred from an image taking unitemployed in the apparatus to the memory means per unit time is smallerthan the amount of information recorded by the information recordingmeans onto the recording medium per same unit time, the amount ofinformation stored in the memory means will decrease gradually. At astage the amount of information stored in the memory means becomes zero,the image taking signal is supplied from the image taking unit directlyto the information recording means employed in the disc drive unit. Thisstate is continued thereafter till the user enters a command to stop therecording operation.

If residual information is left in the memory means at the time the userenters a command to stop the recording operation, the recordingoperation is continued till its completion by recording all the residualinformation onto the recording medium.

As another method, it is also to possible to record an image takingsignal, which has been stored temporarily in the memory means till adisk drive unit employed in the disc drive unit enters a state of beingcapable of recording information, onto a recording medium later. In thiscase, a seek operation is carried out to move a drive head unit to aposition the recording medium. This position on the recording mediumfollows a storage area reserved for the image taking signal storedtemporarily in the memory means. Then, an image taking signal followingthe image taking signal stored temporarily in the memory means issupplied to the information recording means employed in the disc driveunit, taking precedence of the image taking signal stored temporarily inthe memory means. Finally, after the user enters a command to stop therecording operation, the image taking signal stored temporarily in thememory means is recorded into the reserved storage area on the recordingmedium.

The methods described above are each disclosed as a method to avoid astate of being incapable of recording a signal onto a recording mediumafter the power-supply is turned on till the disc drive unit reaches apredetermined rotation.

BRIEF SUMMARY OF THE INVENTION

In the conventional technology described above, the following points arenot specially taken into consideration.

In the first place, after the user turns on the power-supply of theapparatus, an image taking signal is stored temporarily in a memorymeans till a disk drive unit employed in the apparatus enters a state ofa stable rotation. Then, at a stage the disk drive unit employed in theapparatus enters a state of a stable rotation, a recording meansemployed in the disc drive unit starts a recording operation and theamount of information stored in the memory means decreases gradually. Ata stage the amount of information stored in the memory means becomeszero, the image taking signal is supplied from the image taking unitdirectly to the information recording means employed in the disc driveunit. In order to supply the image taking signal from the image takingunit directly to the information recording means, a switching means isrequired. In addition, a switching timing must be identified. In orderto determine a switching timing, the state of rotation must be observedall the time in order to make a difficult decision as to whether tosupply the image taking signal from the image taking unit to the memorymeans or directly to the information recording means.

It is thus a first object of the present invention to provide analgorithm that can be used with ease to eliminate the switching means.

In the second place, the user does not always start a recordingoperation when the power-supply is turned on. In the conventionaltechnology described above, however, neither a method to clearlyidentify a state allowing the user to start a recording operation nor amethod to determine a timing to start a recording operation is speciallydisclosed. It is thus a second object of the present invention toprovide a method to inform the user of the fact that a recordingoperation can be carried out even though operations to activatecomponents employed in the drive have not been completed after the userhas turned on the power-supply of the apparatus.

In the third place, in a step to activate an optical disc drive, inaddition to elements for starting a disc rotation, the followingstepping components are required.

(1) A laser diode and a laser-emission control circuit. The laser diodeis a component for emitting a laser to be radiated to the recordingmedium. The laser-emission control circuit is a circuit for controllingthe output of the laser diode to a magnitude corresponding to a signalto be recorded onto the recording medium or a predetermined magnitude.

(2) An opto-electrical conversion circuit for converting a beam, whichis reflected by the disc recording medium at a quantity corresponding topits and recording marks on the disc recording medium when the laser isemitted at a predetermined output magnitude, into an electrical signal.

(3) An object lens, an actuator mechanism and a control circuit of theactuator mechanism. The object lens is a component for converging thelaser beam. The actuator mechanism is a component for moving the objectlens in the same direction as the optical axis in order to focus thelaser beam on the surface of the disc recording medium in the so-calledfocusing operation and for moving the object lens in the radialdirection of the recording medium in order to place the spot of thefocused laser beam on a desired track of the disc recording medium inthe so-called tracing (or tracking) operation.

(4) A spindle motor, a control circuit of the spindle motor, a base, aslider mechanism and a control circuit of the slider mechanism. Thespindle motor is a component for rotating the disc recording medium. Thebase is a component on which at least the object lens and the actuatormechanism are mounted. The slider mechanism is a component for movingthe base. The base and the slider mechanism are required because, withonly the actuator mechanism for moving the object lens in a trackingoperation, all tracks cannot be accessed.

The circuits including the control circuits cited above need to beoperated sequentially as follows.

In order to record a signal onto an optical disc or reproduce a signalfrom an optical disc, the actuator mechanism described in section (3)and the slider mechanism described in section (4) are controlled byoperating their respective control circuits to focus the laser beam onthe surface of the optical disc and to position the spot of the focusedlaser beam on a desired track of the disc. Then, the laser-emissioncontrol circuit described in section (1) as well as the opto-electricalconversion circuit described in section (2) are operated and, ifnecessary, the control circuit described in section (3) is againoperated properly in order to achieve a state allowing a recording orreproduction operation to be carried out for the first time.

However, the optical disc drive is easily affected by variations fromdisc to disc and variations from apparatus to apparatus. In consequence,it is not easy to execute the proper control described above. In orderto solve this problem, learning control has been much proposed. Thelearning control is executed to find a control value to be set in eachof the control circuits (including mainly the actuator control circuitand the laser-emission control circuit) each time the control value isrequired.

In particular, it takes relatively long times in many cases to executethe learning control of the laser-emission control system to learn arecording optical power and learn an emission timing of the recordingemission power. The emission timing is determined to adjust theso-called time-axis phase, which is referred to simply as a recordingphase for the sake of simplicity.

In addition, the mechanisms described above and the control circuitsystem must be capable of handling a disc of another type in some cases.In such cases, the type of a disc is recognized from a variety ofphysical quantities such as amplitudes of various control feedbacksignals and amplitudes of information reproduction signals. It takes arelatively long time to identify the type of a disc from such physicalquantities. Examples of the control feedback signals and the informationreproduction signals are an error signal of a beam reflected by the discand used in the focusing control or the tracking control and a signalproportional to a rotational speed of the disc. The signal proportionalto a rotational speed is used in control of the disc rotation andembedded on tracks of the disc in advance.

In order to correctly identify the type of the recording medium, it isnecessary to read out information on the recording medium andinformation on a physical format for each medium type from the recordingmedium. The information on the recording medium and the information on aphysical format for each medium type have been recorded on the recordingmedium in advance.

It is also necessary to read out information on medium management fromthe recording medium. The information on medium management isinformation on management of defects in the case of a rewritable disc orinformation on locations to which additional data can be written in thecase of an addable-type disc. It also takes a relatively long time toread out these pieces of information on management. In particular, inthe case of an addable-type disc, it is necessary to verify that alocation at which data was recorded last as described by themedium-management information read out from the recording medium indeedmatches a location preceding a location to which additional data can bewritten. That is to say, it takes a very long time to carry out a stepfor searching the disc recording medium for a location at which data wasactually recorded last.

In accordance with specifications, in an information recording apparatusfor recording information onto a disc recording medium, in addition tothe building-up step of the rotation of the disc to reach a steadystate, there is a number of much-time consuming operations that need tobe completed before a recordable state of the disc is achieved after thepower-supply is turned on.

That is to say, in the case of the conventional described above, thereis specially no description of a technique to avoid a period of timeduring which data cannot be recorded onto the disc recording medium forthe reasons described above. It is thus a third object of the presentinvention to avoid a period of time during which data cannot be recordedonto the disc recording medium for the reasons other than thebuilding-up step of the rotation of the disc to reach a steady state.

In order to solve the problems described above, the present inventionprovides the following means.

In the first place, in order to achieve the first object of the presentinvention, the present invention provides a configuration in which,instead of observing a condition for switching from an unrecordablestate to a recordable state, an operation to supply information storedin a memory means to a recording means employed in a drive is started ata stage the amount of information stored in the memory means exceeds apredetermined quantity.

In the second place, in order to achieve the second object of thepresent invention, the present invention provides a display meansallowing the user to recognize a startable recording state.

In the third place, in order to achieve the third object of the presentinvention, first of all, the present invention provides a means formonitoring operations to mount and dismount the disc recording medium onand from the information recording apparatus. If the means clearlyverifies no replacement of the disc recording medium mounted on thedrive, some or all of the steps that consume much time, causing theproblems described above can be eliminated. The steps include the stepto recognize the type of the disc recording medium, the step to read outthe information on medium management from the disc recording medium orsearch the disc recording medium for a location at which user data wasactually recorded last in the case of an addable-type disc recordingmedium and the step to learn a recording power and a recording phase. Asa result, it is possible to considerably reduce the length of a periodof time during which the information recording means employed in thedrive is put in an unrecordable state after the power-supply is turnedon.

Specifically, the present invention provides a configuration in which,if the disc recording medium is inserted and the power-supply is turnedon for the first time, the user is informed of the fact that anoperation to record data onto the disc recording medium can be startedafter the information recording means for carrying out the activationsteps described above in accordance with a first stepping procedureenters a recordable state. In the same configuration, if thepower-supply is turned on for the second or subsequent time, the user isinformed of the fact that an operation to record data onto the discrecording medium can be started after the information recording meansfor completes operations in accordance with a second stepping procedureeliminating some time-consuming ones of the activation steps describedabove prior to a recordable state.

As described above, the present invention exhibits an effect that asimple algorithm is capable of avoiding an unrecordable state due to,among other causes, the disc rotation's buildup step with a durationequal to a relatively fixed period of stepping time.

In addition, a time-consuming step, which is to be carried out after thepower-supply is turned on, can be eliminated during an activation stepfollowing a second or subsequent power-on operation but not during anactivation step following the first power-on operation in order to avoidan unrecordable state that would take a long time.

Furthermore, by informing the user that an operation to record data ontothe disc recording medium can be started, the user is capable of easilyidentifying a timing to operation to record data onto the disc recordingmedium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory block diagram showing the configuration of anembodiment of the present invention;

FIG. 2 shows first timing charts used for explaining operations carriedout by and embodiment of the present invention;

FIG. 3 shows second timing charts used for explaining operations carriedout by an embodiment of the present invention; and

FIG. 4 shows an explanatory flowchart representing a load step carriedout by a drive controller 12 provided by an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the invention are explained by referring toFIGS. 1 to 4 as follows. An embodiment of the invention implements avideo camera for recording an image signal onto an optical disc. Theimage signal is a signal obtained as a result of an image takingoperation carried out by an image taking unit employed in the videocamera. The description begins with an explanation of operations ofcomponents and a configuration comprising the components with referenceto FIG. 1.

First of all, implementation of a means for mounting and demounting adisc on and from a disc drive unit is explained.

Reference numeral 1 denotes a cover of a case for accommodating anoptical disc 3. Reference numeral 2 denotes a switch for detecting anopened or closed state of the cover 1. The cover switch 2 is connectedto a system controller 22. The system controller 22 is a microsteporpowered by a main battery 29 through a main power-supply switch 31, apower-supply series regulator circuit 33 and a power-supply changeoverswitch 32 or by a backup battery 30 through the power-supply seriesregulator circuit 33 and the power-supply changeover switch 32. Thus,even if power-supply switch 31 is turned off, cutting off the powersupplied by the main battery 29 to the system controller 22, anoperation carried out by the system controller 22 is continued, enablingthe system controller 22 to receive a signal indicating theopened/closed state of the cover 1 from the cover switch 2. As a result,the system controller 22 is capable of recognizing the possibility thatthe optical disc 3 has been mounted or demounted on or from the case foraccommodating an optical disc 3.

Next, a control means for controlling a spindle motor is explained.

Reference numeral 4 denotes a spindle motor for driving the rotation ofthe optical disc 3. The spindle motor 4 outputs a signal proportional toits own rotational speed to a spindle motor control circuit 5. Thespindle motor control circuit 5 measures a period and a phase of thesignal proportional to the rotational speed and compares the measuredperiod and the measured phase with a target period and a target phaserespectively. The spindle motor control circuit 5 then outputsspeed-error signals representing a difference between the measuredperiod and the target period as well as a difference between themeasured phase and the target phase to the spindle motor 4 in order tocontrol the spindle motor 4.

In addition, an opto-electrical conversion circuit 16 detects afrequency signal included in a beam reflected by the optical disc 3 andsupplies the frequency signal to the spindle motor control circuit 5.The frequency signal is proportional to the rotational speed of theoptical disc 3. The frequency signal is embedded in advance in tracks onthe optical disc 3 as a format. The spindle motor control circuit 5generates a control signal and outputs the control signal to the spindlemotor 4 in order to control the rotational speed of the spindle motor 4to a predetermined rotational speed. To put it in more detail, thespindle motor control circuit 5 adjusts the rotational speed of thespindle motor 4 so that the frequency signal read out from the tracks ofthe optical disc 3 approaches a value corresponding to the predeterminedrotational speed as much as possible.

Next, the spindle motor control circuit 5 for controlling the spindlemotor 4 is explained.

Reference numeral 9 denotes a slider mechanism on which an object lens7, an actuator mechanism 8, a laser diode 14 and the opto-electricalconversion circuit 16 are mounted. Reference numeral 10 denotes a slidermotor. The slider motor 10 is typically a micro-step motor. Referencenumeral 11 denotes a slider-motor control circuit for receiving a setvalue from a drive controller 12 and outputting a two-phase rectangularor sinusoidal driving signal to the slider motor 10. The frequency ofthis driving signal determines a distance by which the slider mechanism9 is to be moved.

Next, an actuator control means for controlling the actuator mechanism 8is explained.

The actuator mechanism 8 is a component for controlling the object lens7. To put in detail, the actuator mechanism 8 moves the object lens 7 inthe direction of the optical axis and the radial direction of theoptical disc 3 in accordance with a control signal generated by anactuator-servo control circuit 17. The actuator-servo control circuit 17generates focusing and tracking error signals on the basis of anelectrical signal obtained as a result of an opto-electrical stepcarried out by the opto-electrical conversion circuit 16 on a beamreflected by the optical disc 3. The actuator-servo control circuit 17then outputs the control signal to the actuator mechanism 8 aftercarrying out proper control compensation.

Next, an information recording and reproduction means for recording andreproducing a signal onto and from the optical disc 3 is explained.Reference numeral 14 denotes a laser diode. A laser beam emitted by thelaser diode 14 hits the object lens 7. The output of the laser diode 14is controlled by a laser driver 15. The laser driver 15 controls thelaser beam emitted by the laser diode 14 to a predetermined output valuein a reproduction operation. In a recording operation, on the otherhand, the laser driver 15 controls the laser diode 14 to emit a laserbeam corresponding to a modulated signal as much as possible. Themodulated signal is received from a modulation and demodulation circuit18. The laser driver 15 is switched from a recording mode to areproduction mode and vice versa by a driver controller 12.

A beam reflected by the surface of the optical disc 3 is supplied theopto-electrical conversion circuit 16, being converted into anelectrical signal, which is then fed to the modulation and demodulationcircuit 18. The modulation and demodulation circuit 18 demodulates theelectrical signal. The modulation and demodulation circuit 18 is alsoswitched from a modulation mode to a demodulation mode and vice versa bythe driver controller 12.

By referring to FIG. 2, the following description explains operationscarried out by an apparatus at the upper level of the drive unit shownin FIG. 1.

The description begins with an explanation of a state in which thepower-supply switch 31 is put at an OFF position. With the power-supplyswitch 31 put at an OFF position, the power-supply changeover switch 32is put at a position of selecting the backup battery 30. In this state,power is supplied by the backup battery 30 to the system controller 22by way of the power-supply series regulator circuit 33 so that thesystem controller 22 is capable of monitoring the cover switch 2 and apower-supply on/off command switch 6.

Assume that, in this state, the user enters a command to turn on thepower by operating the power-supply on/off command switch 6. In thiscase, the system controller 22 turns on the power-supply switch 31. Whenthe power-supply switch 31 is turned on, the power-supply changeoverswitch 32 is switched by a switching signal to a position of selectingthe main battery 29. The switching signal is also used by a reset-signalgeneration circuit 41 as a base for switching the system controller 22from a low power consumption mode in which power is supplied from thebackup battery 30 to a normal mode. Time charts shown in FIG. 2 indicatea timing with which the power-supply switch 31 is turned on by apower-on command from the system controller 22.

In this state, the system controller 22 also activates a power-supplycircuit 26. When activated, the power-supply circuit 26 generates apower-supply signal 36 supplied to a variety of components and a resetsignal 35 supplied to the driver controller 12. Receiving the resetsignal 35, the driver controller 12 enters a state of waiting for acommand to be transmitted from the upper level unit by way of a packetinterface circuit 19.

If the cover switch 2 is changed from an opened state to a closed statewhile the power-supply switch 31 is at the OFF position, the systemcontroller 22 informs the memory controller 21 of the change in state.

Informed of the change in state, through the packet interface circuit19, the memory controller 21 issues a request to the driver controller12 to carry out an activation step according to a first activationmethod at a point of time indicated by an arrow Load 1 in FIG. 2.Receiving the request, the driver controller 12 activates a power-supplyswitch 40 in the drive unit to start an operation to supply power to avariety of components employed in the drive unit during a period of timeindicated by notation Load in FIG. 2.

An example of this activation step is represented by a flowchart (1) ofFIG. 4. As shown in the figure, the flowchart begins with a step s101 atwhich the actuator-servo control circuit 17 is operated to drive theactuator mechanism 8 to carry out a lens-down step (s101). In thelens-down step, the object lens 7 is moved away from the optical disc 3.Then, at the next step s102, the laser driver 15 is operated to drivethe laser diode 14 to emit a laser beam at a predetermined emissionpower. In this way, the laser beam is radiated all of a sudden to thesurface of the optical disc 3 without being focused.

Subsequently, at the next step s103, the driver controller 12 operatesthe actuator-servo control circuit 17 to drive the object lens 7 up anddown in the direction of the optical axis. A beam reflected by theoptical disc 3 can thus be obtained through the opto-electricalconversion circuit 16 when the object lens 7 passes through an areaaround the focus point. A first stage classification step based on theamplitude of the reflected beam and other information is carried out.

Then, at the next step s104, the driver controller 12 operates thespindle motor control circuit 5 to start rotating the spindle motor 4.At this stage, the spindle motor control circuit 5 controls the spindlemotor 4 by using a signal proportional to the rotational frequency ofthe spindle motor 4. The signal is generated by the spindle motor 4itself.

Subsequently, at the next step s105, the driver controller 12 againoperates the actuator-servo control circuit 17 to drive the actuatormechanism 8 to move the object lens 7 up and down in order to focus thelaser beam on the surface of the optical disc 3.

As the laser beam gets focused on the surface of the optical disc 3, itis possible to observe a track-crossing signal indicating that the laserbeam crosses a track created on the optical disc 3 due to eccentricityof the optical disc 3 itself of eccentricity existing in the spindlemotor 4. Then, at the next step s106, the driver controller 12 furthercarries out a second step to classify the types of the optical disc 3 onthe basis of information including the amplitude of the track-crossingsignal supplied to the actuator-servo control circuit 17 from theopto-electrical conversion circuit 16. It is thus possible to roughlyidentify the physical type of the optical disc 3.

Subsequently, at the next step s107, the driver controller 12 operatesthe actuator-servo control circuit 17 to make a track indicated by thetrack-crossing signal follow the laser beam.

At this stage, preparations to read out information from the track onthe optical disc 3 have been completed. Then, at the next step s108, thedriver controller 12 reads out recording-medium information recorded inadvance on a specific track prescribed by format specifications of theoptical disc 3. The information on the recording medium theoreticallyconfirms the type of the optical disc 3.

Subsequently, at the next step s109, the driver controller 12 reads outinformation on medium management. In the case of a rewritable disc, theinformation on medium management includes defect management informationindicating a location on the surface of the disc at which a defectexists and indicates a spare recording location allocated as asubstitute for the defective location. In order to assure safety, theinformation on defect management is generally copied and the informationand its copies are recorded at a plurality of recording locations on thesurface of the optical disc 3. In order to grasp the most reliable pieceof information on defect management among the pieces of information ondefect management, all the pieces of information on defect managementare read out to determine the most reliable piece of information ondefect management in case it is quite within the bounds of possibilitythat the optical disc 3 is replaced.

In the case of an addable-type disc, on the other hand, the informationon medium management includes information indicating a location on thesurface of the optical disc 3 at which data was recorded last. In thecase of an addable-type disc, it is necessary to verify that thelocation at which data was recorded last indeed matches a locationpreceding a location to which additional data can be actually written.Thus, at the next step s110, the driver controller 12 searches theoptical disc 3 for the location at which additional data can be actuallywritten on the basis of the location at which data was recorded last.

What is described above is a first activation method. For the sake ofconvenience, a period of time indicated by notation Load in FIG. 2 isdivided into sub-periods denoted by Setup, Judge and Read. The Setupsub-period of time is a sub-period during which the spindle motor 4 andthe actuator mechanism 8 are controlled. The Judge sub-period of time isa sub-period during which the type of the optical disc 3 is identified.The Read sub-period of time is a sub-period during which the informationon the medium or the information on the medium management is read outfrom the optical disc 3 or the optical disc 3 is searched for a locationto which additional data can be added in the case of an addable-typedisc.

Let us go back to the description of a case, in which the cover 1 wasopened before the power-supply was turned on, with reference to FIGS. 1and 2.

While the activation step is being carried out by the driver controller12 in accordance with the first activation method, the system controller22 requests the memory controller 21 to receive no request to start arecording operation from the user. In order to inform the user that norequest to start a recording operation is accepted, the memorycontroller 21 displays a message, which indicates that a step torecognize the type of the optical disc 3 is going on, on aliquid-crystal monitor 25, by driving a compression and decompressioncircuit 24 to superpose the message on the image taking signal.

As the memory controller 21 is notified of the fact that the activationstep carried out by the driver controller 12 in accordance with thefirst activation method has been completed through the packet interfacecircuit 19, the memory controller 21 passes on the notification to thesystem controller 22, and displays a message, which indicates that arecordable state has been reached, to the user on the liquid-crystalmonitor 25 in the same way as the message, which indicates that a stepto recognize the type of the optical disc 3 is going on, during a periodreferred to as a Rec Pause period in FIG. 2.

Receiving the notification, the system controller 22 starts an operationto monitor a button switch 27 to be operated by the user to enter acommand to start or stop a recording operation.

If the system controller 22 does not detect an operation carried out bythe user to enter a command to start a recording operation, the memorycontroller 21 issues a request to the driver controller 12 to stopoperations in order to save energy. Receiving the request, the drivercontroller 12 stops the operations of the components and turns off thepower-supply switch 40 in order to avoid the waste of power.

In this state, when the user operates the button switch 27 to enter acommand to start a recording operation at a point of time indicated byan arrow Rec Start in FIG. 2, the system controller 22 accepts thecommand and passes on the command to the memory controller 21.

The memory controller 21 passes on the command to start a recordingoperation to the driver controller 12 as indicated by an arrow Writeshown in FIG. 2. At the same time, a signal output by the image takingcircuit 23 is encoded by the compression and decompression circuit 24and an operation to start storing information in a memory circuit 20 iscarried out. In addition, a message indicating that the recordingoperation has been started is displayed to the user on theliquid-crystal monitor 25 in a period called Display during Rec in FIG.2.

Receiving the command to start a recording operation, the drivercontroller 12 turns on the power-supply switch 40 to resume theoperation of the stopped spindle motor 4, the emission of a laser beamand the control of the actuator. Since the step of acquiring informationfor recognizing the type of the optical disc 3 and information on mediummanagement as well as the step to verify a location on an addable-typedisc to which data is to be added have already been completed, theactivation step merely to resume the operation of the mechanism controlsystem and to resume the emission of the laser beam can be completed ina relatively short period of time.

Since learning steps to find optimum values of the recording powersupplied to the recording medium and the recording phase have not beencarried out, however, the learning steps to find optimum values of atleast either the recording power or the recording phase or both therecording power and the recording phase need to be carried out duringthe step of storing the image taking signal in the memory circuit 20.

The learning steps to find optimum values of the recording power and therecording phase are carried out in a trial-and-error manner to evaluatea condition, in which data is written onto the optical disc 3, byactually storing data onto the optical disc 3 while changing parametersfor adjusting the recording power and the recording phase from time totime.

Thus, in the case of a rewritable disc, since an area for storing datain the trial-and-error step can be used repeatedly, the learning stepsto find optimum values of the recording power and the recording phasecan be carried out as part of the first-activation-method-basedactivation step following the power-on operation as described earlier.

In the case of an addable-type disc, on the other hand, an area forstoring data in the trial-and-error step cannot be used repeatedly.Thus, there is a limit on the number of times the trial-and-error stepcan be carried out on a disc. For this reason, the learning steps tofind optimum values of the recording power and the recording phase arenot carried out as part of the first-activation-method-based activationstep following the power-on operation. Instead, the learning steps arecarried out when there is actually a request for such steps.

Even if the learning steps are completed, the memory controller 21 doesnot start a recording operation immediately. Instead, the memorycontroller 21 starts a recording operation after the amount ofinformation of the image taking signal stored in the memory circuit 20exceeds a first predetermined quantity.

As the recording operation is started, the amount of information storedin the memory circuit 20 gradually decreases. When the amount ofinformation stored in the memory circuit 20 decreases to a value smallerthan a second predetermined value, the memory controller 21 stops therecording operation. In addition, in order to reduce the amount of powerconsumed by the drive unit till the recording operation is resumed, thedriver controller 12 is requested to stop operations. As requested, thedriver controller 12 stops operations of the components and turns offthe power-supply switch 40 in order to decrease power consumption.

With the recording operation stopped, the amount of information storedin the memory circuit 20 again increases. As the amount of informationstored in the memory circuit 20 reaches a value slightly smaller thanthe first predetermined quantity, the memory controller 21 makes arequest for the activation of the driver controller 12. Receiving therequest, the driver controller 12 again turns on the power-supply switch40 to operate the spindle motor control circuit 5, the laser driver 15and the actuator-servo control circuit 17. This time, since the learningsteps of the recording power and the recording phase have beencompleted, the recordable state can be reached in a short period oftime.

The intermittent operations described above are carried out repeatedlytill the user operates the button switch 27. As the user operates thebutton switch 27 to enter a command to stop the recording operation at apoint of time indicated by an arrow Rec Stop in FIG. 2, the systemcontroller 22 detects this command and informs the memory controller 21that the recording operation is to be stopped. Receiving thisnotification, the memory controller 21 stops an operation to supply theimage taking signal to the memory circuit 20 thereafter and changes thedisplay appearing on the liquid-crystal monitor 25 to a state of beingready to start a recording operation. In addition, the memory controller21 issues a request to the driver controller 12 to stop operations afterwaiting for all residual information left in the memory circuit 20 to berecorded by the drive unit onto the optical disc 3. Receiving thisrequest, the driver controller 12 stops operations of components andturns off the power-supply switch 40 in order to decrease powerconsumption.

In this state, when the user operates the button switch 27 to enter acommand to start a recording operation at a point of time not shown inFIG. 2, the system controller 22 accepts the command and passes on thecommand to the memory controller 21. Receiving the command, the memorycontroller 21 starts a recording operation to store the image takingsignal in the memory circuit 20. Thereafter, the intermittent operationsare carried out repeatedly in the same way as described above.

When the user operates the power-supply on/off command switch 6 with therecording operation stopped to make a request to cut off power suppliedto the whole apparatus at a point of time indicated by arrow Power Offin FIG. 2, on the other hand, the system controller 22 detects thisrequest and passes on this request to the memory controller 21. Thememory controller 21 also informs the driver controller 12 that thepower supplied to the whole apparatus is to be cut off.

Informed that the power supplied to the whole apparatus is to be cutoff, the driver controller 12 saves the type of the disc recordingmedium currently mounted on the disc drive as well as the learningvalues of the recording power and the recording phase in a non-volatilememory circuit 13. In the case of an addable-type disc, the drivercontroller 12 also saves the information on matching between the lastrecording location included in the information on medium management andan actual recording location in the non-volatile memory circuit 13. Inthe case of a rewritable disc, on the other hand, the driver controller12 also saves data such as information on validity of pieces ofinformation on defect management recorded at a plurality of locations,that is, information indicating which pieces of information on defectmanagement are valid, into the non-volatile memory circuit 13. After thestep to save the information in the non-volatile memory circuit 13 iscompleted, the driver controller 12 notifies the memory controller 21 ofthe completion. Receiving this notification, the memory controller 21passes on the notification to the system controller 22. Informed thatthe step to save the information in the non-volatile memory circuit 13has been completed, the system controller 22 stops the operation of thepower-supply circuit 26 in order to terminate a step to supply power tothe drive unit and the image taking block. Thereafter, the systemcontroller 22 merely continues execution of a program for monitoring thepower-supply on/off command switch 6 and the cover switch 2, turning offthe power-supply switch 31 in order to receive power-only from thebackup battery 30 in a power-saving operation.

The above description explains the operations, which are carried outwhen the user enters a command to turn on the power-supply to furnishpower to the whole apparatus if the cover 1 has been opened and closedwith the power-supply cut off, indicating that it is quite within thebounds of possibility that the optical disc 3 has been replaced withanother one. Next, by referring to FIGS. 1, 3 and 4 (2), the followingdescription explains operations, which are carried out when the userenters a command to turn on the power-supply furnishing power to thewhole apparatus if an operation to open and close the cover 1 has notbeen recognized at all with the power-supply cut off, indicating that itis out of the bounds of possibility that the optical disc 3 has beenreplaced with another one.

First of all, when the user operates the power-supply on/off commandswitch 6 to enter a command to turn on the power-supply, the systemcontroller 22 detects this operation. At that time, the systemcontroller 22 switches the source supplying power to itself from thebackup battery 30 to the main battery 29. In addition, the systemcontroller 22 operates the power-supply circuit 26 to carry out stepsincluding an operation to supply power to the drive block and the imagetaking block through a power-supply line 36 in the same way as what hasbeen described earlier by referring to FIG. 2.

The system controller 22 notifies the memory controller 21 that anoperation to open and close the cover 1 has not been recognized during aperiod of time in which the power-supply is cut off. Receiving thisnotification, the memory controller 21 issues a command to carry out anactivation operation according to a second activation method to thedriver controller 12 at a point of time coinciding with an arrow Load 2shown in FIG. 3.

Receiving the command, the driver controller 12 starts activation of thedrive unit in a second-activation-method-based activation steprepresented by a flowchart shown in FIG. 4 (2). Details of the flowchartare explained as follows.

As shown in the figure, the flowchart begins with a step s201 at whichinformation is read out from the non-volatile memory circuit 13. Asdescribed in the explanation of the operations with reference to FIG. 2,the information read out from the non-volatile memory circuit 13includes the type of the disc recording medium currently mounted on thedisc drive as well as the learning values of the recording power and therecording phase. In the case of an addable-type disc, the informationread out from the non-volatile memory circuit 13 also includes theinform on matching between the last recording location included in theinformation on medium management and an actual recording location. Inthe case of a rewritable disc, on the other hand, the information readout from the non-volatile memory circuit 13 also includes data such asinformation on validity of information on defect management recorded ata plurality of locations, that is, information indicating which piecesof information on defect management are valid. The flow of the steppingthen goes on to the next step s202 to form a judgment as to whether ornot all pieces of information have been gathered and there will be noproblems even if a recording operation is started. If all pieces ofinformation have been gathered and there will be no problems even if arecording operation is started, the flow of the stepping goes on to astep s203 at which the memory controller 21 is notified that all piecesof information have been gathered and there will be no problems even ifa recording operation is started. Receiving this notification, thememory controller 21 displays a message indicating that a recordingoperation can be started on the liquid-crystal monitor 25 during aperiod of time indicated by Rec Pause in FIG. 3.

Refer back to the flowchart shown in FIG. 4 (2). Since the type of theoptical disc 3 has been recognized from the information read out fromthe non-volatile memory circuit 13, the driver controller 12 operatesthe spindle motor control circuit 5, the laser driver 15 and theactuator-servo control circuit 17 in an order they are enumerated hereat steps s204, s205, s206, s207 and s208 in order to transit to a statein which information can be read out from the optical disc 3. If allinformation on the medium has been stored in the non-volatile memorycircuit 13, it is not necessary to carry out an operation to read outinformation from the optical disc 3. Since some information exists inthe optical disc 3, however, in this embodiment, the information is readout from the optical disc 3 at the next step s209.

Then, at the next step s210, one valid piece of information on mediummanagement is read out from the optical disc 3 if the optical disc 3 isa rewritable disc. Since information indicating which pieces ofinformation on defect management are valid has been stored in thenon-volatile memory circuit 13, however, the operation of the step s210can be completed in a short period of time.

In the case of an addable-type disc, on the other hand, the informationstored in the non-volatile memory circuit 13 also includes the inform onmatching between the last recording location included in the informationon medium management and an actual recording location. Thus, the searchstep can be eliminated. As a result, the operation of the step s210 canalso be completed in a short period of time as well.

As described above, for a disc experiencing an activation step accordingto the first activation method in the past, the time it takes to carryout an activation step can be shortened substantially. Thus, it ispossible to display a message indicating that the resumption of arecording step is allowable on the liquid crystal monitor 25 during aperiod of time indicated by Rec Pause in FIG. 3. That is to say, if thedriver controller 12 is requested to implement the second activationmethod, the memory controller 21 informs the user that the resumption ofa recording step is allowable without waiting for a report ofactivation-step completion to be issued by the driver controller 12 aslong as there is no condition for objections in data stored in thenon-volatile memory circuit 13 (for example, as long as the user did notmake a request for an operation to cut off power before the type of therecording medium could be identified when the drive unit was activatedby adoption of the first activation method).

Refer back to the time charts shown in FIG. 3. If the user operates thebutton switch 27 to enter a command to start a recording operation whilethe driver controller 12 is activating the drive unit by adoption of thesecond activation method, the system controller 22 detects this commandand passes on the command to the memory controller 21. Receiving thiscommand, the memory controller 21 starts an operation to store the imagetaking signal in the memory circuit 20. Since the activation stepaccording to the second activation method can be completed in arelatively short period of time as described above, the activation stepaccording to the second activation method can be completed before theamount of the image taking signal stored in the memory circuit 20exceeds the first predetermined quantity. Thus, the memory controller 21may start an actual recording operation as soon as the amount of theimage taking signal stored in the memory circuit 20 exceeds the firstpredetermined quantity in the same way as that explained earlier byreferring to the time charts shown in FIG. 2 without taking theoperation of the driver controller 12 into consideration.

Thereafter, the amount of information stored in the memory circuit 20gradually decreases and intermittent recording operations are carriedout repeatedly in the same way as that explained earlier by referring tothe time charts shown in FIG. 2. In addition, if the user enters acommand to stop the recording operation to be followed by a command tocut off power supplied to the whole apparatus, operations are carriedout also in the same way as that explained earlier by referring to thetime charts shown in FIG. 2.

Thereafter, if the optical disc 3 is not replaced with another one whileno power is being supplied to the whole apparatus, a subsequent step totransit to a recordable state at power-on is carried out by adoption ofthe second activation method described above. Thus, the user is allowedto enter a command to start a recording operation without the need towait for the activation step to be completed.

1. An information recording apparatus for recording information,comprising: a buffer memory which stores information; a recordingportion which records information that is stored in the buffer memoryonto a recording medium; a command portion to initiate storinginformation into the buffer memory; a power-supply portion to supplypower; a power-supply switch to connect and disconnect the power fromthe power-supply portion respectively to and from the recording portion;a non-volatile memory; and a control portion which reads out relevantinformation from the non-volatile memory beginning when the power-supplyswitch connects the power from the power-supply portion to the recordingportion and, when the relevant information is judged to satisfy apredetermined condition, then the control portion signals the commandportion to initiate storing information into the buffer memory at a timeprior to the recording portion being able to record information onto therecording medium, wherein the non-volatile memory stores a memorycapacity of the recording medium, an initial recording position, and adefect information of the recording medium as the relevant information,wherein the recoding portion starts to record information onto therecording medium on the basis of the relevant information.
 2. Theinformation recording apparatus according to claim 1, wherein when it isdetermined that the relevant information does not satisfy thepredetermined condition, then the control portion signals the commandportion to initiate storing information into the buffer memory at a timeafter the recording portion is able to record information onto therecording medium.